1. Field of the Invention
The present invention relates to a vacuum processing apparatus and a vacuum processing method for processing a substrate by supplying a gas into a process chamber under a vacuum atmosphere.
2. Description of the Related Art
A film deposition apparatus that performs an ALD (Atomic Layer Deposition) method disclosed in Japanese Laid-Open Patent Application Publication No. 2011-151387 is, for example, known as an apparatus and a method to deposit a thin film such as a silicon oxide SiO2) film on a substrate such as a semiconductor wafer (which is hereinafter called a “wafer”). The film deposition apparatus includes a horizontal turntable in a process chamber that is evacuated and made a vacuum atmosphere, and the turntable includes a plurality of concave portions in which a wafer is accommodated in a circumferential direction of the turntable. A plurality of gas nozzles is arranged so as to face the turntable. For example, the plurality of gas nozzles include gas nozzles for forming processing atmospheres by supplying process gases (reaction gases) in order to deposit a silicon oxide film, and gas nozzles for supplying a separation gas that separates the processing atmospheres from each other above the turntable. The gas nozzles for supplying the process gases and the gas nozzles for supplying the separation gas are alternately arranged above the turntable in the process chamber.
The film deposition apparatus includes lifting pins movable up and down so as to penetrate a bottom of the concave portions. A wafer transferred by a transfer mechanism is supported by the tops of the lifting pins. The wafer is transferred to the bottom of each of the concave portions by intermittently rotating the turntable and by moving the lifting pins up and down.
In the meantime, when transferring the wafer from the transfer mechanism into the concave portion in this manner, it is noted that the wafer is sometimes placed in a position that is shifted from a position where the wafer should be placed normally. This is thought to be due to a gas that remains in the concave portion even though the inside of the process chamber is made a vacuum atmosphere when transferring the wafer. More specifically, when the wafer is lowered toward the bottom of the concave portion in a state in which the gas is left inside the concave portion, the wafer does not contact the bottom of the concave portion due to the remaining gas, goes into a state of floating, and moves laterally by sliding.
Moreover, the wafer transferred by the transfer mechanism to the turntable sometimes has warpage. Furthermore, even when the wafer does not have warpage during the transfer by the transfer mechanism, the wafer may warp due to a non-uniform temperature within a surface of the wafer caused by heat received from the turntable when lowering toward the bottom of the concave portion. When such a warped wafer floats up due to the gas inside the concave portion and moves laterally, a periphery of the wafer is liable to run on an edge of the concave portion. In addition, when the turntable is rotated in such a state, the wafer comes out of the concave portion by a centrifugal force due to the rotation and an air current formed in the process chamber, and a normal film deposition process is unlikely to be performed on the wafer. Japanese Laid-Open Patent Application Publication No. 2011-151387 does not disclose any measure to solve such a problem.